package com.dyz.leetcode._20_dynamicProgramming._121;

public class maxProfit01 {
    /*
   dp[i][0][0] = 0
   dp[i][k][0] = max(dp[i - 1][k][0], dp[i - 1][k][] + prices[i][])
   dp[i][k][1] = max(dp[i - 1][k][1], dp[i - 1][k-1][0]-prices[i])

   k只交易一次，跟k无关， 因为只能交易一次，所以dp[i - 1][k-1][0]=0
    dp[i][0][0] = 0
    dp[i][0] = max(dp[i - 1][0], dp[i - 1][1] + prices[i])
    dp[i][1] = max(dp[i - 1][1], 0-prices[i])
    */
    public int maxProfit(int[] prices) {
        int[][] dp = new int[prices.length][2];

        dp[0][0] = 0;
        dp[0][1] = -prices[0];

        for (int i = 1; i < prices.length; i++) {
            dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] + prices[i]);
            dp[i][1] = Math.max(dp[i - 1][1], -prices[i]);
        }

        return dp[prices.length - 1][0];
    }
}
